Extrudable elastomeric compositions which can be easily compression molded or melt blown into elastic sheets or films having low stress relaxation, low hysteresis, and high recoverable energy are described in U.S. Pat. Nos. 4,663,220, 4,789,699, and 5,093,422. The elastomeric sheets or films are useful in making stretchable laminates with stronger films for a variety of applications such as diaper waistbands and legbands.
Styrene-poly(ethylene-butylene)-styrene elastomeric block copolymers and styrene-poly(ethylene-propylene)-styrene elastomeric block copolymers have been blended with other materials such as, for example, polyolefins and tackifying resins to form extrudable elastomeric compositions which can be more easily extruded into elastic sheets having improved processing and/or bonding properties. While the additives improve the extrusion properties of the compositions and the processing and/or bonding properties of the elastic sheet, such additives may, in certain situations, have an adverse affect on the elastic properties of the resulting sheet. For example, such elastomeric block copolymers blended with large amounts of a polyolefin and/or hydrocarbon resin may have poor stress relaxation properties and stress-strain tests of such materials show significant hysteresis.